use os.devnull for python2 support

plugin/packages/wakatime/wakatime/projects/subversion.py

@@ -12,7 +12,7 @@
 import logging
 import os
 import platform
-from subprocess import Popen, PIPE, DEVNULL
+from subprocess import Popen, PIPE
 
 from .base import BaseProject
 try:
@@ -54,6 +54,7 @@ class Subversion(BaseProject):
             '/usr/local/bin/svn',
         ]
         for location in locations:
+            with open(os.devnull, 'wb') as DEVNULL:
                 try:
                     Popen([location, '--version'], stdout=DEVNULL, stderr=DEVNULL)
                     self.binary_location = location